A federal magistrate ordered 33-year-old Luke Daniel Wiersma of Dyer, Indiana, held without bond until a Friday detention hearing. He was arrested Tuesday. Federal prosecutors say Wiersma posted online threats at least seven times last October and November through the clinics' websites.

Prosecutors say Wiersma allegedly says in one threat that he will "do anything and everything to stop the unmitigated murders of fetuses." He also said, "I will blow you up if I have to, burn the clinic down."

Wiersma is charged with transmitting threats to injure and using threats of force to intimidate or interfere with reproductive health services.

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